Centrifugal pumping system



NOV. 21, 1933. A PETERSQN 1,936,066

CENTRIFUGAL PUMPING SYSTEM AFiled oet. 15, 1951 Patented Nov. 21, 1933 l Y l UNITED. STATES PATENT OFFICE Y 1,936,066 CENTRIEUGAL PUMPING SYSTEM Arvid Peterson, Trenton, N. J., assignor to De Laval Steam Turbine Company, Trenton, N. J., a. corporation of New Jersey Application October 15, 1931. Serial No. 568,948 4 Claims. (Cl. 103-112) This invention relates to a centrifugal pump- The casing of a multistage centrifugal pump ing system particularly designed for use in conof the type used for boiler feed purposes is illusnectlon with centrifugal pumps handling hot watrated at 2. Mounted in this casing is the shaft ter for boiler feeding purposes. 4 carrying the impellers 5 arranged in series in 5 A high-pressure boiler feed pump when operthe usual manner. The first stage receives water 6o ating,` against'closed dischargey or at very low cathrough the suction inlet 6. In order to secure pacties will very quickly become vapor-bound proper operation a balancing arrangement indidueto the churning of the water within the pump cated at 8 is provided including a balancing cham- Which increases its temperature so that flashing ber 10 into which some liquid from the discharge 10 into `steam `will result; One of the reasons for passes and out of which liquid leaks in the usual y65 this is that the Water discharge from the balancfashion to provide a proper axial balance of the ing chamber isftaken' into the suction nozzle of rotary parts against the tendency to move tomost multistage pumps. As this water may be of wards the suction. appreciably higher temperature than the water The leakage water from the balancing chamentering the pump the resultant temperature of ber enters a suitable annular chamber connected 70 water entering the rst stage is often high enough with an outiiow pipe l2 which opens into a valve to produce rapid evaporation at the reduced prescasing 14, the valve in the present instance being sure of the suction. In order to improve the opof the plug variety. The plug 16 is provided with Y eration of such pumps at low capacities and passages 24 and 26 as illustrated, the passage 24 shut-off pressures, they are also provided with extending diametrically through the plug while 75j bypass connections from the discharge stage into the passage 26 extends at right angles through the suction. However, 'this also causes higherone side of the plug from the passage 24. A hantemperature water to mix with the water enterdle 18 `connected to the plug provides for its maning the pump and the same kind of trouble may ual manipulation, suitable stops 20 and 22 being result. Furthermore, this system decreases the provided to limit the `motion of the plug in the 80;-`

chcchcy 0f the Dump by ah amOllht cOllcSDOndpresent instance to a right angle. Communicating to the Water that is bypassed. ing with a port the center of which is 90 from It is the broad object of the present invention the port opening from pipe l2 is a pipe 28 which to provide a pumping system designed to handle connects the valve casing with the suction inlet water at relatively high temperatures which will 6. A second pipe 30 extends from a port located 85Vv avoid the objections of the systems heretofore diametrcally opposite the entrance port and conin use. Briefly, the invention involves running nects the interior of the valve casing with the the balancing leakage water into the usual heater inflow conduit 32 leading to the heater 34 located Where the temperature caIlIlOll bc higher than between the source of water and the suction of 35 that corresponding to the pressure in the heater. the pump. 9o: Such bypass accomplishes two advantageous re- The sizes of the passages 24 and 26 are S0 sults. First, it provides a bypass when the pump made that at no time will the flow through 12 is Operating at 10W Capacities 0r Shut-Off preS- be interrupted. That is, either the passage 24 SulcS- Secchdly, il? pI'cVch'CS high tcmpcatulc or 26, or both, are at all times in communication 4o water from entering the Suction 0f the Dump with the entrance port communicating with pipe 95gv which would be detrimental even when Operating 12. Likewise, one of the other of the ends of at ccmpalatvcly large caDac'cS- The byDaSS the passage 24 is at all times in communication furthermore does not decrease the emciency of with one 0r both of the discharge ports, so that the Dump ih the hflilhhcl a bypass from the dS- the water from 12 is either passing through pipe charge chamber into the suction or into the 23 er pipe 30, 0r beth, The stops 20 and 22 are 100 heater WOUlClprovided to insure that the flow of Water from MOI@ Specifically, il? iS the Object 0f the IlVehthe balancing chamber is never interrupted, tion to provide an arrangement which will takev since if this flow were stopped destruction of the care of various conditions of operation as will be pump might quickly result.

more clearly understood from the following de- The heater 34 may be of any usual type either 105* Scrptcn read irl ccnjuhctcl With the accomhaving large storage space or being open to the Dahyhg drawing in Which the flgllc illustrates atmosphere. Since the Water that is admitted in axial vertical section, and diagrammatically, through the baineing pipe te the heater is quite a. pumping System in aCCOIdaIlCe With the nVeIlsmall in amount as Compared With the Volume Y tion.

of Water in the heater, there Will be practically lli);y

no temperature rise of the aggregate Water entering the pump and therefore no evaporation. If the heater is of the closed type and a large amount of hot water entered, there would immediately be a release of vapor. On the other hand, if the heater were of the closed type, the pressure would rise slightly. The heater may be, as is generally the case, supplied With cold Water by a separate pump. While the pipe 30 is shown as entering the main inlet to the heater it may obviously enter any part of the heater so long as the Water entering through it Will mingle with relatively large amounts of Water in the heater prior to entrance into the pump.

If pro-vision Were made to run the balancing Water into the heater alone the pump could not be shipped as a self-contained unit and could not be operated unless the pipe connection to the eater was provided. By the use of a three-Way plug valve in the balancing line the balancing Water may be bypassed either tothe suction or to the heater. By the arrangement shown, the three-way valve may be used in any` position to secure the proper operating conditions; that is. the flow may be apportioned in any desirable fashion between the pipes 28 and 30.

What I claim and desire to protect by Letters Patent is:

1. In combination, a centrifugal pump having a balancing chamber, an inlet passage to the pump, means for heating Water entering the inlet passage, and means forleading leakage Water from the balancing chamber directly into the heating means and into admixture With the Water being heated therein.

2. In combination, a centrifugal pump having a balancing chamber, an inlet passage to the pump, means for heating Water entering the inlet passage, and means for leading leakage Water from the balancing chamber either directly into the heating means and into admixture with the Water being heated therein or into the inlet passage.

3. In combination, a centrifugal pump having a balancing chamber, an inlet passage to the pump, means for heating Water entering the inlet passage, and means for leading leakage water from the balancing chamber either directly into the heating means and into admixture with the Water being heated therein or into the inlet passage, said last named means including a valve operable to control the alternative flows.

4. In combination, a centrifugal pump having a balancing chamber, an inlet passage to the pump, means for heating Water entering the inlet passage, and means for leading leakage Water from the balancing chamberleither directly into the heating means and into admixture with the Water being heated therein or into the inlet passage, said last named means including a 'valve' operable to control the alternative flows, the valve being so arranged that free passage for flow from the balancing chamber is assured at all times.

VARVID PETERSON.

Y lll 

